1. Field of the Invention
The present invention relates to semiconductor devices, and more specifically to decoupling between a noise emitter and a noise-sensitive receiver that are in an integrated circuit formed on a semiconductor-on-insulator type substrate.
2. Description of Related Art
The coupling noise in an integrated circuit essentially comes from two sources, namely the electromagnetic coupling due to the package and metal lines of the circuit and the electrical coupling due to the substrate (e.g., SOI substrate). The present invention is directed to reducing the electrical coupling noise due to the substrate. In particular, when a noise emitter injects charges into the substrate, the charges become distributed uniformly and then can be picked up by a receiver whose operation may be perturbed if it is sensitive to this electrical noise. For example, a "noise emitter" in the context of this description can be a strong-signal transistor that injects charges into the substrate, and the charges can be picked up by a weak-signal transistor, which then behaves as a noise-sensitive receiver. As an exemplary environment, such strong and weak-signal transistors can be incorporated into radio messaging receivers.